Recently, researches on an MOFF channel having a multi-orifice segment have been reported.
However, such researches are only at the initial stage at home and abroad. In particular, the application of an MOFF channel to the medical world is in a very immaterial state.
Breast cancer is the first cancer rate in women even in Korea as well as in U.S.A. Lifetime incidence means a possibility that a specific disease will occur through life. In U.S.A., the lifetime incidence of breast cancer is 1/6, and one of 6 persons has breast cancer through lift.
In Korea, the frequency of an attack of breast cancer was about 20 persons per 100,000 persons 10 years ago, but breast cancer patients are suddenly increasing, that is, 50 persons or more per 100,000 persons in 2008. Furthermore, although the cause of breast cancer is not clear, in U.S.A., an attack of breast cancer increases with age and the most breast cancer occur in persons in the sixtieths˜seventies, whereas in Korea, the most breast cancer occur in persons the 40's. A sudden increase of an attack rate and the most attack in the forties are a great social problem personally, domestically, and in terms of national economy.
In particular, breast cancer, unlike thyroid cancer frequently occurred in women, is not treated by only a surgical operation, but is cancer that requires a very complicated treatment process of 6 months to 1 year or more, such as anticancer drug treatment, hormone treatment, radiation treatment, and target treatment even after the operation. However, despite such various and long-term treatment, 30˜40% of all breast cancer patients needs to experience medication again due to recurrence and metastasis. Nevertheless, most of patients whose cancer recurs lead up to death.
In the case of a cancer patient, the greatest influence on mortality depends on the presence or not of metastatic cancer cells. That is, technology in which one Circulating Tumor Cell (CTC) needs to be found in 109 red cells within blood very precisely without a loss of a cell is much-needed technology in order to improve a survival rate before and after cancer treatment of patients.
In blood of about 7.5 ml, CTCs less than 5 need to be found in the case of breast cancer, CTCs less than 3 need to be found in the case of colorectal cancer, and CTCs less than 5 need to be found in the case of prostate cancer. Microcell separation technology that satisfy three basic conditions 1) throughput (the number of cells that may be separated per time), 2) cell recovery (a ratio of the number of injected target cells and the number of separated and recovered target cells), and 3) separation efficiency (purity, degree of purity of separated and recovered target cells) is necessary.
CTC metering methods disclosed so far may be classified into a genetic metering method using Polymerase Chain Reaction (PCR), a metering method using centrifugal separation and magnetophoresis, a fluorescent dyeing method, and a method using a filter. Most of the methods are disadvantageous in that reliability of diagnosis is low because target cells are lost due to a pre-processing process of removing a large number of blood cells included in blood in order to detect a CTC.
Representatively, CellSearch that was solely approved by FDA as a CTC diagnostic tool includes a pre-processing process for samples and an analysis process for refined samples. The pre-processing process is disadvantageous in that a CTC may be missed in a pre-processing step because it includes several steps along with a process of processing Anti-EpCAM using magnetic particles, mixing the Anti-EpCAM with the blood of a patient, and separating a CTC using magnetism. A loss of samples in detecting a CTC known to be present as one concentration in 109 cells is an important problem that is directly connected to the accuracy of diagnosis.
Accordingly, there is a need for a microfluid system in which steps from a pre-processing process to the final diagnosis process are continuously integrated as a method using the size, density, and modification, that is, physical characteristics inherent in a CTC. Furthermore, a CTC separated using the microfluid system needs to be analyzed using optical equipment in real time, and a clinician must perform molecular analysis into the verified CTC.
A current anticancer adjuvant therapy is performed on almost most of patients without checking the presence or not of such a CTC. Anticancer drugs are equally administrated to patients based on the results of clinical tests because there is no method of checking whether or not such anticancer drug treatment help the patients individually. In fact, patients whose cancer recurs although anticancer drugs are not administrated to the patients exceed half of all breast cancer patients, but most of patients including such patients experience anticancer drug treatment because it is not known when cancer will recur in what patients.
A research hypothesis that unnecessary anticancer drug treatment can be reduced by selecting patients whose cancer may recur through detection and analysis researches into a CTC. Furthermore, by taking that fact that cancer recurs in 30˜40% of all patients despite a surgical operation and an anticancer adjuvant therapy into consideration, it is determined that anticancer treatment effects will be more smooth only when anticancer drugs effective in a CTC, that is, the eventual cause of recurrence, are used. Accordingly, researches into the detection and analysis of a CTC are considered to be an important foundation in developing more effective anticancer drugs in the future.
In recent various molecular biological techniques, various types of cancer cells can be tested using a blood test. In particular, a method of finding and diagnosing a Circulating Tumor Cell (CTC) within blood, which is known as a cell that enters blood and circulates the body, from among cancer cells, is a very effective technique in early diagnosing a cancer patient and determining prognosis after treatment, but a successful case thereof is rare.
With the recent development of a molecular biological diagnostic method having high sensitivity, a clinical base that may be used in the molecular staging of cancer patients, the prediction of prognosis, and the early detection of recurrence. As various types of molecular biological schemes based on PCR are automated, the sensitivity of a test is improved, an analysis process is simplified, and an analysis time is reduced.
Accordingly, it is necessary to develop a system capable of separating and metering a CTC using blood samples obtained from a cancer patient. The development of such a system will help more understanding of a molecular structure of a cell that is necessary to check cancer through CTC researches and clarify the characteristics of a cancer cell and a cancer cell metastatic process.